Radiofrequency ablation of renal tumours with clinical, radiographical and pathological results

Abstract

Objectives To evaluate our experience with radiofrequency ablation (RFA) for renal masses and to report on clinical, radiological and post-RFA biopsy results. Patients and methods The study collected clinical, radiological and pathological data from 150 consecutive patients who were treated with RFA of a renal mass between 2002 and 2008 at a tertiary referral centre. Post-ablation biopsies were performed in patients with non-involuting lesions or suspicion of recurrence on imaging. Comparisons were performed using the Mann–Whitney U-test. Survival was estimated using the Kaplan–Meier method. Results Renal malignancy was found in 72.1% of patients based on the initial diagnostic biopsy. Median tumour size was 2.6 cm, 22.7% of patients had a solitary kidney, and most were central tumours. The mean follow-up period was 40.1 months. There was no recurrence in 96.7% of the entire cohort. Cancer-specific survival for 106 patients with sporadic, localized, biopsy proven renal malignancy was 100% at 38.5 months. Biopsies were obtained in 43 patients for a median of 21 months after RFA. Among 38 patients who had biopsy for non-involuting, non-enhancing zones of ablation, three (7.9%) were positive. Conclusions Short-term cancer-specific survival after RFA remains excellent and most cases are successful based on a combination of imaging and post-ablation biopsies performed almost 2 years after treatment. There were four out of 150 (2.7%) patients who had recurrences with tissue confirmation; one of these patients was detected on imaging and three (2%) were radiologically occult. The absence of enhancement in the setting of non-involuting lesions is not always a guarantee of a successful ablation.

Salvage surgery after energy ablation for renal masses

“…The median (IQR) R.E.N.A.L. nephrometry score at time of surgery was 7 (5)(6)(7)(8)(9), while the median (IQR) time from ablation to surgery was 26.5 (16. .3) months.…”

“…Surgery was performed in two patients because of tumour progression with renal vein or inferior vena cava thrombus, in three patients because of failure of the tumour to shrink (with a positive preoperative biopsy) and in nine patients because of enhancement with contrast or tumour enlargement. Seven patients had percutaneous biopsy confirming recurrent disease, some of whom have been previously reported as part of our RFA experience [8]. Patients underwent surgery at the median (IQR) time of 26.5 (16.3-39.3) months after the ablation was performed.…”

“…Options for treating small renal masses include active surveillance, energy ablation using radiofrequency ablation (RFA) or cryoablation, or surgery using partial or radical nephrectomy [5][6][7]. Given that energy ablation is typically a percutaneous procedure, especially in the case of RFA, ablative techniques have seen an increase in popularity; they have a relatively low morbidity profile and favourable effectiveness, especially in older patients and in patients with multiple medical comorbidities [8].…”

“…For this reason, we normally perform open partial nephrectomy in patients who have undergone cryoablation, while patients who have previously undergone RFA, particularly if performed percutaneously, can be potentially considered for minimally invasive partial nephrectomy, depending on the tumour location and amount of desmoplastic reaction predicted on preoperative imaging. We do not routinely perform preoperative percutaneous renal biopsies after ablation, but reserve them for those patients with clearly enlarging, enhancing masses or masses with lack of shrinkage >6 months after ablation, as previously described [8]. Our pathologists routinely assess microscopic surgical margins in patients treated with partial nephrectomy, which in the present study, led to the discovery of one focal microscopic positive margin (but grossly negative) in a patient with von Hippel-Lindau disease.…”

Laparoscopic Radiofrequency Ablation versus Partial Nephrectomy for cT1a Renal Tumors: Long-Term Outcome of 179 Patients

“…However, Karam et al [31] recently reported their experience of post-RFA radiographic features, and suggested that the absence of enhancement in tumors does not guarantee a successful ablation. Weight et al [32] also suggested radiologic findings were not reliable and recommended follow-up biopsy post RFA.…”